The invention relates to a process of fabricating an elongated glass body, particularly a preform for optical waveguides on the basis of SiO.sub.2, in which a porous body is formed from powdery glass starting material and such body is sintered to obtain the glass body.
One such process is described in a copending commonly owned U.S. Pat. application Ser. No. 703,793, in which it is proposed to fill powdery glass starting materials with compositions changing in the radial direction under precompaction, into a compression mold from several coaxially disposed conveyor tubes. The fill-in pressure effecting the pre-compaction is effected therein either by screw conveyors or by a centrifugal force. In any case, the coaxial arrangement of various conveyor tubes and the simultaneous conveyance of different materials involves a considerable investment in appartus, which is a pronounced disadvantage.